#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
#include<string>
using namespace std;
struct TreeNode {
    int val=0;
    TreeNode* left=nullptr;
    TreeNode* right=nullptr;
    TreeNode() : val(0), left(nullptr), right(nullptr) {}
    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
    TreeNode(int x, TreeNode* left, TreeNode* right) : val(x), left(left), right(right) {}
};
class Solution {
public:
    string tree2str(TreeNode* root) {
        string str;
        if (root == nullptr)
            return str;
        str += to_string(root->val);
        if (root->left || root->right)
        {
            str += '(';
            str += tree2str(root->left);
            str += ')';
        }
        if (root->right)
        {
            str += '(';
            str += tree2str(root->right);
            str += ')';
        }
        return str;
    }
};
int main()
{
    return 0;
}